Finding the Fourth Proportional to 142.86, 214.37 and 82.05

Step by Step Solution

1. Step 1: Write the proportion equation
   142.86 : 214.37 = 82.05 : x
2. Step 2: Convert to fraction form
   142.86/214.37 = 82.05/x
3. Step 3: Cross multiply
   142.86x = 214.37 × 82.05
4. Step 4: Simplify right side
   142.86x = 17,589.06
5. Step 5: Solve for x
   x = 17,589.06/142.86
6. Step 6: Final answer
   x = 123.12